Your answer isn't really wrong, it's just not as direct. Ultimately, the closer the pixels are together, the more you'd have per square inch. So you're still sort of right anyhow! LOL
The literal answer though, is that dot pitch is the measurement between pixels. But yeah, it's been a long time since I've even talked specs on CRTs. I have an old Samsung monitor my wife just dragged out of a storage closet. Forgot I even had it.